Audiophiles hifi appreciation thread old and new

i could be wrong here, but i'm guessing that
8+8 =16
4+4=8
and your speakers are 8 ohms

That would be wrong :) , speaker impedance is specified per speaker - so connect the 8ohm taps on the amp to the speaker

Firstly, apologies if this is a stupid question, but i can't seem to find a straight answer online.

I recently got my hands on a Pioneer SA5300 which I want to connect to some KEF iq70 speakers. The amp's got two sets of speaker outputs - two 8 ohms and two 4 ohms, and the speakers are 8 ohms. Am I right in thinking that to biwire the speakers, I connect two cables to each of the 8 ohms outputs and leave the 4 ohms outputs unconnected?

Correct, although biwiring is pretty much foo in my opinion (bi-amping is somewhat different and *can *bring sonic improvement).